In recent years, computers have played an increasing role in the design of mechanical parts. Current trends toward complete design automation have motivated the development of Mechanical Computer-Aided Design (MCAD) systems equipped with powerful analytical tools that enable designers to iteratively optimize and refine designs prior to prototyping.
Current MCAD systems incorporate the traditional keyboard and stylus or mouse input devices. While familiar, these devices may be clumsy and difficult to use and may actually hinder designer creativity. Consequently, MCAD systems are used primarily in the latter stages of the design process for numerically intensive analysis and detailed drawing. One of the primary limitations of these devices is that they are inherently two dimensional. Three dimensional information can not be directly transmitted to the system. It is believed that the primary reason many systems are used as design verification tools rather than as true design tools is that their human interfaces are too awkward. These interfaces do not offer designers the flexibility to easily create and modify a design.
Various recent research efforts that focusing on three dimensional input devices have used the Polhemus 3 Space six degree of freedom input device. This device uses low frequency magnetic waves to provide 3-D position and orientation of sensor relative to a stationary source. VPL Research, Redwood City, Calif. has incorporated Polhemus devices in their "Eyephone" and "DataGlove" products. The former is a head mounted display device that provides the user with a stereoscopic view of a virtual world. The Polhemus sensor tracks 3-D head movements and enables the computer to match the viewer's position and orientation in the virtual world with their absolute position and orientation in the real world. The "DataGlove" is literally a glove worn on a user's hand that sends different signals to the host computer based on the user's hand postures. A Polhemus sensor mounted near the wrist tracks the 3-D position of the user's hand in 3-space. When used together, the "Eyephone" and "DataGove" enable users to interact with the virtual world.